Abstract
Purpose: :
The ophthalmic branch of the trigeminal ganglion supplies sensory nerves to the cornea. Our aim is to develop a stereotactic approach to reproducibly apply agents to the trigeminal ganglia that can modulate corneal neurobiology.
Methods: :
Six to 8 week-old male C57BL/6 mice were deeply anesthetized and immobilized within a neurosurgical stereotactic frame. Following removal of the superficial dermal layer and bone, a 35g microinjection needle was passed to previously published stereotactic coordinates for the trigeminal ganglia. India ink dye was microinjected through the needle. Following injection, the animal was sacrificed and the true localization of the injected ink was compared to the expected location of the injection. Initial comparative data was used to refine the stereotactic coordinates corresponding to the ophthalmic branch of the trigeminal ganglion and the reproducibility of these revised co-ordinates evaluated in littermates of the initially examined animal.
Results: :
Using the published coordinates on 4 mice from 4 different litters to inject the India Ink to their V1 nerve, only in 1 out of the 4 mice (25%) the injected ink was located on the V1 nerve. In the other 3 mice the true V1 location was found to differ from the injected ink location by an average of +0.08mm on the x axis, -0.5mm on the y axis, and -0.36mm on the z axis. After revising the coordinates according to the true V1 location and using them to inject the India ink to the V1 nerve of each mouse’s littermates, in 3 out of the 4 litters (75%) the injected ink was located at the true V1 location.
Conclusions: :
Establishment of a reproducible system of microinjection at the ophthalmic branch of the trigeminal nerve was achieved. This system can be used to apply agents such as nerve growth factors, analgesics, or gene vectors at the cell bodies corresponding to the nerves providing sensation of the cornea. The system may improve our ability to study basic and translational aspects of corneal neurobiology.
Keywords: cornea: basic science • wound healing